<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<style type="text/css">
			body {
				margin: 0;
				padding: 0;
			}
		</style>
	</head>
	<body style="height: 2000px;width: 2000px;">
	</body>
	<script type="text/javascript">
		// 可视区: 看得见的区域
		// clientHeight  不包含滚动条.超出界面的宽高不获取
		// offsetHeight 含滚动条
		console.log('clientHeight', document.documentElement.clientHeight);
		console.log('offsetHeight', document.documentElement.offsetHeight);
		
	</script>
</html>
